In a conventional solar module, approximately 3% of the usable solar cell surface is shaded by the so-called cell connectors. To reduce these losses, various cell concepts have been worked out which shift the electric contact arrangement of the cells to the unilluminated rear. If it is possible to feed the light reflected from the frontal solder connections back to the active cell area, such complex and costly cell concepts could be bypassed.
One possibility of recapturing the light reflected at the so-called soldering strips consists in using suitably patterned soldering strips (as described in WO 2007/067304 A2). By impressing a trench pattern into the soldering strip, impinging light is reflected at an ideally very flat angle. If the electrically contacted solar cells are encapsulated in a solar module, e.g. in an EVA matrix and glass on the sun side, light reflected at a shallow angle from the pattern of the cell connectors can be conducted back into the module due to the total reflection at the transition from glass to air. A comparable solution is provided, e.g. by the LMS technology from Schlenk. The disadvantages in this case are that the soldering strips must be impressed on both sides and the copper surface does not include very high reflection. For this purpose, a thin layer of a well-reflecting material, usually silver, is applied. The solder must therefore be applied to the solar cell in a separate step in the form of a soldering paste and there is a risk that during the soldering, solder passes around the strip and fills parts of the pattern up again.
Furthermore, cell connectors patterned in this manner are clearly more expensive than conventional cell connectors so that approximately 50% of the commercial benefits are consumed by increases in material costs. As well, these cell connectors cannot be soldered conventionally since both sides of the cell connector must be coated for this. There is also a risk that the light trap patterns are covered with solder and thus become inactive. The price of such strips is also approximately twice or three times as high compared with the price of other conventional cell connectors.